Use the well as a simple effect on an element to give it an inset effect.
<!DOCTYPE HTML>
<html>
<head>
<link href="http://java2s.com/style/bootstrap.min.css" rel="stylesheet">
<!-- ww w. j a va 2s. co m-->
<script src="http://java2s.com/style/jquery-1.8.0.min.js"></script>
<script src="http://java2s.com/style/bootstrap.min.js"></script>
</head>
<body style='margin:20px;'>
<div class="well">
Look, I'm in a well!
</div>
</body>
</html>
Control padding and rounded corners with two optional modifier classes.
<!DOCTYPE HTML>
<html>
<head>
<link href="http://java2s.com/style/bootstrap.min.css" rel="stylesheet">
<!--from w w w . ja v a2s . com-->
<script src="http://java2s.com/style/jquery-1.8.0.min.js"></script>
<script src="http://java2s.com/style/bootstrap.min.js"></script>
</head>
<body style='margin:20px;'>
<div class="well well-lg">
Look, I'm in a well!
</div>
</body>
</html>
<!DOCTYPE HTML>
<html>
<head>
<link href="http://java2s.com/style/bootstrap.min.css" rel="stylesheet">
<!-- ww w .ja v a 2s . com-->
<script src="http://java2s.com/style/jquery-1.8.0.min.js"></script>
<script src="http://java2s.com/style/bootstrap.min.js"></script>
</head>
<body style='margin:20px;'>
<div class="well well-sm">
Look, I'm in a well!
</div>
</body>
</html>